A piece 5

A piece of cloth is laid at the center of a table 80 cm long and 60 cm wide, and it leaves 5 cm all around. Find the area which is not covered by the piece of cloth.

Correct answer:

A =  1500 cm²

Step-by-step explanation:

$$\begin{gathered} a=80\text{cm} \\ b=60\text{cm} \\ h=5\text{cm} \\ x=a+2\cdot h=80+2\cdot 5=90\text{cm} \\ y=b+2\cdot h=60+2\cdot 5=70\text{cm} \\ {S}_1=a\cdot b=80\cdot 60=4800{\text{cm}}^2 \\ {S}_2=x\cdot y=90\cdot 70=6300{\text{cm}}^2 \\ A=S_2-S_1=6300-4800=1500{\text{cm}}^2 \end{gathered}$$

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